Are you saying you believe Aboriginals aren't human but Homo Erectus?
Nope. We're all human. There is only one species of humans and all this Homo-this and Homo-that is hog wash.
All of the features of (so-called) 'extinct humans' can be found in humans today all over the world. If you put all the uniqueness of any combination of these 'traits' together (obtained from modern humans today) you can come up with any Homo-? you desire. It's called "The Multi-regional Theory'. The idea is covered thoroughly in Professor Milford Wolpoff's new book titled: Race And Human Evolution.
There has only ever been one human.